Phenylketonuria (PKU) — Effects of Kuvan on Melatonin Secretion
Citation(s)
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Kaufman S, Kapatos G, McInnes RR, Schulman JD, Rizzo WB Use of tetrahydropterins in the treatment of hyperphenylalaninemia due to defective synthesis of tetrahydrobiopterin: evidence that peripherally administered tetrahydropterins enter the brain. Pediatrics. 1982 Sep;70(3):376-80.
Lou H Large doses of tryptophan and tyrosine as potential therapeutic alternative to dietary phenylalanine restriction in phenylketonuria. Lancet. 1985 Jul 20;2(8447):150-1.
Nielsen JB, Lou H, Güttler F Effects of diet discontinuation and dietary tryptophan supplementation on neurotransmitter metabolism in phenylketonuria. Brain Dysfunction 1:51-56. 1988.
Pilot Study to Evaluate Melatonin Secretion as a Marker of Decreased Serotonin in Individuals With PKU: Evaluation of the CNS Effects of Tetrahydrobiopterin
Interventional studies are often prospective and are specifically tailored to evaluate direct impacts of treatment or preventive measures on disease.
Observational studies are often retrospective and are used to assess potential causation in exposure-outcome relationships and therefore influence preventive methods.
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Clinical trials are conducted in a series of steps, called phases - each phase is designed to answer a separate research question.
Phase 1: Researchers test a new drug or treatment in a small group of people for the first time to evaluate its safety, determine a safe dosage range, and identify side effects.
Phase 2: The drug or treatment is given to a larger group of people to see if it is effective and to further evaluate its safety.
Phase 3: The drug or treatment is given to large groups of people to confirm its effectiveness, monitor side effects, compare it to commonly used treatments, and collect information that will allow the drug or treatment to be used safely.
Phase 4: Studies are done after the drug or treatment has been marketed to gather information on the drug's effect in various populations and any side effects associated with long-term use.
